This invention relates to decomposition of phthalic acid esters by use of microorganisms. Phthalic acid esters are used chiefly as plasticizers in plastic products. Gradually these phthalic acid esters dissolve out of plastic products and mingle into water, air and other similar natural elements. Since phthalic acid esters generally are sparingly soluble in water, the phthalic acid esters which dissolve out little by little into nature continue to accumulate in nature. In recent years, as a result of the sharp increase in the production of plastic products, pollution of the environment by such accumulating phthalic acid esters has risen rapidly to the extent of arresting public attention, posing a grave social issue equivalent to that once encountered with PCB.
Decomposition of phthalic acid esters by microorganisms of certain species belonging to genus Bacillus has been reported (Collection of Abstracts of Lectures at the 1975 General Meeting of Japan Agricultural Chemical Society, page 43 (1974). The method introduced in this report effectively converts diheptyl phthalates into corresponding monoheptyl phthalates. However, phthalic acid esters such as di-2-ethylhexyl phthalate, dibutyl- benzyl phthalate and dibutyl phthalate which are major plasticizers used in plastic products are not decomposed at all by this method.
An object of this invention is to provide a method which permits easy decomposition of all the phthalic acid esters into water and carbon dioxide gas.